Digital data storage systems are known. In particular, digital tape recording systems employing a single-reel tape cartridge are known. In one known system for digital data storage as shown in FIG. 1, a magnetic tape drive uses a single-reel tape cartridge 22. A tape drive 10 is generally comprised of a rectangular housing 30 that has a common base 18 carrying two spindle motors. A first spindle motor 15 rotates a permanently mounted take-up reel 14 dimensioned to accept a relatively high speed streaming magnetic tape 20. A second spindle 25 is adapted to rotate a feed reel 24 of the single-reel removable tape cartridge 22. The removable tape cartridge 22 is manually or automatically inserted into tape drive 10 via a suitably-dimensioned slot 32 formed in the drive's housing 30. Upon insertion of the tape cartridge 22 into the slot, the cartridge tape feed reel 24 becomes engaged by the second spindle motor 25. Prior to synchronized rotation of the first spindle motor 15 and second spindle motor 25, the tape cartridge leader becomes automatically buckled to a drive take-up leader extending from the take-up reel 14 along the tape path 26 within the drive 10. Newer versions of the tape drive 10 use a different buckling mechanism to join the cartridge leader to the take-up leader. Cartridges using the newer buckling mechanism cannot be used in older systems, because the cartridge leader in the newer cartridges will not successfully mate with the take-up leader of older tape drives.
In the event that a tape cartridge designed for use in a newer tape drive is inserted into a tape drive 10 having an older buckling mechanism, the cartridge leader and the take-up leader associated with the older buckling mechanism will not successfully buckle. As a result, the take-up leader will disengage from the buckling mechanism and spool on to the take-up reel 14. Further, the take-up leader will spool on to the take-up reel without magnetic tape 20 from the tape cartridge 22 being connected thereto. This condition is known as take-up leader run away. A technician is typically required to service a tape drive 10 that has been subjected to a leader run away condition in order to re-position the take-up leader on the buckling assembly.
In newer tape drives enhanced read/write head structures and data processing electronics are capable of storing and processing increased lineal track and bit densities on the magnetic tapes. If a tape cartridge employing these increased lineal track and bit densities is used with an older tape drive that does not incorporate the enhanced head structures and data processing electronics, the data previously stored on the cartridge will be overwritten and erased. As a result, tape cartridges that are recorded with these increased lineal track and bit densities are not backwards compatible with older tape drives that do not employ the enhanced read/write head structures and data processing electronics.
The problem can be stated generally in a simple manner: newer cartridges are not compatible with earlier tape drives. However, older cartridges need to be compatible for use with newer tape drives, as the archival data stored on older cartridges may be needed long after the older tape drive has been replaced by a newer model.
Recently, most manufactures of tape drives and their components agreed upon a standard form factor for cartridges produced by cartridge manufacturers. As a result, however, the form factor of one family of storage medium cartridges cannot be appreciably modified to distinguish older cartridges from newer cartridges without violating the standard. Therefore, the above described compatibility problems associated with storage medium cartridges employing the positive engagement buckling mechanism and/or the enhanced read/write head structures and data processing electronics cannot be alleviated by simply changing the form factor of the cartridge.
Therefore, a need exists for a new tape cartridge that has the same form factor as an older tape cartridge, but which cannot be inserted into or used with older tape drives. At the same time, whatever modification is made to prevent the usage of new cartridges in old drives cannot prevent the use of old cartridges in new tape drives.